i was thinking, instead of having a bunch of isFoo() functions, except maybe isPlainObject(), it would be useful to integrate and expose something like this for detecting object types:

http://snipplr.com/view/12492/getclass/

syntactically it would get a bit more verbose for reuse, eg jQuery.typeOf([]) == "Array", but it can be abstracted away by isArray() as is currently if it needs to be used in many places.

however, $.typeOf() might provide a good foundation and replacement for isFunction isArray, etc...

in the current nightly usage count:
66x typeOf
35x isFunction
13x isArray
2x isBool

i have not benchmarked it at all, might be slower? thoughts?
Leon